1. Field of the Invention
This invention relates to a capsule endoscope adapted to be introduced into an object of examination and equipped with various function executing means for executing predetermined functions in order to collect information from the inside of the object of examination and a substrate bearing such function executing means. A capsule endoscope according to the present invention may typically be of a swallowable type.
2. Description of the Related Art
Capsule endoscopes that are equipped with an image pickup function and a wireless communication function have become available in the field of endoscope in recent years. A capsule endoscope that is swallowed by a subject, or an object of examination, for observation (physical examination) is then driven to move through the inside of the stomach, the small intestine and other organs (the body cavity) as the organs peristaltically wave until it is naturally excreted from the living body of the subject so as to pick up images of the inside of the body by means of its image pickup function during the period of observation. The image data of the images picked up in the body cavity by the capsule endoscope during the period of observation are sequentially transmitted to an external unit arranged outside the object of examination by means of the wireless communication function such as Bluetooth and accumulated in the memory of the external unit. As the subject carries the external unit having a wireless communication function and a memory function with him or her, he or she, whoever appropriate, can move without restrictions during the period of observation from the time of swallowing the capsule endoscope to the time of excreting it. After the observation, the images picked up from the body cavity can be displayed on a display screen by a doctor or a nurse for diagnosis according to the image data accumulated in the memory of the external unit.
Known capsule endoscopes include those of a swallowable type as disclosed in Patent Document 1 (JP 2007-14634-A) that are also equipped with the above listed functions. Such a capsule endoscope includes a lighting member (a light emitting diode to be referred to as LED hereinafter), an image sensor, drive circuits for them, a power supply section including a battery and a transmission section for transmitting image data from the image sensor to an external unit, which are arranged on respective arrangement substrates as so many IC. The substrates are then connected to each other by way of a strip substrate, and all the components are contained in a hermitically sealed and capsule-shaped container having dome-shaped opposite ends.
The above-cited Patent Document 1 that discloses a an indwelling device for capsule type medial apparatus also describes that the holding section thereof is partly provided with anti-stain coating such as hydrophilic coating typically of a photocatalyst in order to minimize the influence of the apparatus on observation. Such hydrophilic coating of a photocatalyst has been and being finding applications in various fields. For example, Patent Document 2 (JP 2003-207601-A) proposes an objective lens to be used for an optical pickup of an optical disk device. The surface of the objective lens is coated with a hydrophilic photocatalytic material that is excited by light having a wavelength not greater than 420 nm. The photocatalytic material becomes so hydrophilic that it produces a contact angle with water substantially equal to 0° when excited with light having a wavelength not greater than 420 nm. Then, if moisture adheres to the surface of the lens, it does not form any fine droplets but becomes a thin water film on the surface. Thus, the objective lens is hardly clouded if the environment changes.
Patent Document 3 (JP 2005-312809-A) describes a technique of forming a thin film containing a photocatalyst on the outer surface of a light transmitting member arranged at the front end of an optical member of the part of an endoscope, a medical endoscope in particular which may typically be a hard mirror or a soft mirror, to be inserted into the body cavity of a subject for the purpose of observing and treating the inside of the subject.